A wide array of storage tanks and containers are used for holding and transporting various types of fluids. For example, most motorized vehicles, such as the modern-day automobile, are manufactured with an internal fuel tank for safely storing combustible petroleum-based fuel, such as gasoline and diesel. Personal fuel containers, more commonly known as “gas cans” or “gas caddies”, are also available for manually transporting smaller quantities of fuel.
Fuel tanks are traditionally refilled at public gas stations. Most are designed to receive a fill pump nozzle in order to replace the contents of the container. To comply with legal regulations, nearly all fill pump nozzles include an automatic shutoff mechanism for discontinuing the flow of fuel from the nozzle when the fuel in the container reaches a predetermined position or level. Typically, a fill-limiting sensors is triggered when the fuel tank is full, and fuel begins to “back up” the filler neck to reach or spray the fill-limiting sensor. Even with an automatic shutoff mechanism, fuel pump operators may inadvertently overfill a fuel tank in an to fill the container “completely”.
Many fluid storage containers, such as those used in automobiles, include a spout or inlet fluidly coupled to the tank body by an elongated filler pipe. Small gas tank configurations, for example those used in motorcycles, boats, personal watercraft, commercial law equipment, all-terrain recreational vehicles, gas cans, etc. may not have a fill neck. Be that as it may, small gas tanks are often designed to have the liquid level near the opening of the tank when full. Consequently, small gas tanks may prematurely trigger the fill-limiting sensor on the fill pump nozzle before the container is completely filled because the fill-limiting sensor, when inserted into the tank, may be several inches below the intended full level. To offset this feature, many operators do not insert the nozzle completely into the opening, which often leads to an overflow spill.
Overfilling a storage tank may result in damage to the tank, vehicle, or filling equipment, contamination of land or ground water, or other serious results. Concerns over spillage of the tank contents are particularly acute when the tank contents are flammable, toxic, or environmentally hazardous. Some contemporary estimates of such fuel spillage are in excess of six million gallons annually in the United States alone. The resultant fuel losses are economically and ecologically detrimental in terms of wasted fuel resources and environmental contamination.